Bikefit with Wrench Science bike fit
#1
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Hi! Are the measurements with wrenchscience technically correct in relation to general bicycle geometry and recommended to be used or only an indication as long as the measurement itself is carried out accurately?
Thanks & Regards
hsea17
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hsea17
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Are you asking if they are exactly correct for everyone with any bicycle?
#3
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10-12 years ago I had a "Retul - Fit" and I have more or less followed that measurement ever since. But a couple of days ago I had help measuring myself and entered the measurements on the web page of Wrench Sience and even though I have decreased a little in height as I age, many other measurements were the same as before. But what I don't understand are the measurements that came out on reach and stack and especially how I can end up with a so short reach and what kind of frame comes with that reach or how to fit myself to a reach as that

Below are a screen shot of results from Wrench Sience
hsea17

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I've not used Wrench Science. In fact I've never used any. But I've toyed with a few just to see what they do. It just seems that they all are simply using measurements to put your body in a certain position on the bike. Some ask you up front what type of position you prefer. And basically that's either a relaxed upright position or a aggressive racing position and maybe a in between third position.
So the bigger difference with any of these tools is how detailed they get in the bike measurements as well as your measurements.
Regardless, IMO, finding a bike to fit what some have told me is darn near impossible unless I had a custom made bike. If Wrench Science or any other has a database of bike models and their geometries and other measurements and could suggest a bike model for you based on the fit you choose, then that would be somewhat beneficial. However even still, when the bike is set up for you by their measurements for saddle, seat fore/aft/tilt and other things, then still it's only a starting point to refine the adjustments.
So the bigger difference with any of these tools is how detailed they get in the bike measurements as well as your measurements.
Regardless, IMO, finding a bike to fit what some have told me is darn near impossible unless I had a custom made bike. If Wrench Science or any other has a database of bike models and their geometries and other measurements and could suggest a bike model for you based on the fit you choose, then that would be somewhat beneficial. However even still, when the bike is set up for you by their measurements for saddle, seat fore/aft/tilt and other things, then still it's only a starting point to refine the adjustments.
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I had the same thing with Wrench Science's bike fit calculator. Their web site in general is an enigma to me. I try to save something and it is maybe not saved, the fit calculations are very different from every single bike I currently ride, etc. All my current road bikes are 61 cm top tube with a 110 cm stem and they recommended a 56 cm top tube. Let me think... no way I fit on a 56 cm top tube bike.
Their web site support guy was very prompt in answering my questions, but was also very defensive: their web site is not a buggy pile of steaming poo. Their products look very good, and I am considering a fairly high end build from them, but it will not be using their fit.
Also, I can't delete individual components from a build. I want to use some stuff on my "rack o' junk" for my next build but their online configuration doesn't support that. But if I chat with them they can do it and send me the price. So not a good web site. A very fancy web site, but not very good. But what do I know. The only web sites I have written have been control panels on industrial automation systems.
Their web site support guy was very prompt in answering my questions, but was also very defensive: their web site is not a buggy pile of steaming poo. Their products look very good, and I am considering a fairly high end build from them, but it will not be using their fit.
Also, I can't delete individual components from a build. I want to use some stuff on my "rack o' junk" for my next build but their online configuration doesn't support that. But if I chat with them they can do it and send me the price. So not a good web site. A very fancy web site, but not very good. But what do I know. The only web sites I have written have been control panels on industrial automation systems.
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No we are all varieties and some more then another that includes myself it seems!
10-12 years ago I had a "Retul - Fit" and I have more or less followed that measurement ever since. But a couple of days ago I had help measuring myself and entered the measurements on the web page of Wrench Sience and even though I have decreased a little in height as I age, many other measurements were the same as before.
10-12 years ago I had a "Retul - Fit" and I have more or less followed that measurement ever since. But a couple of days ago I had help measuring myself and entered the measurements on the web page of Wrench Sience and even though I have decreased a little in height as I age, many other measurements were the same as before.
I've got some geriatric compression going on, too. Nearly all of it's in the spine, so I know my saddle height won't change.But I see a shorter stem sometime in my future. If you've been happy with your Retul fit, I suggest you do something similar.
My proportions have been confounding numbers-based fit systems since 1980, starting with the Fit Kit. Wrench Science put me on a 59 cm frame with a 54 cm top tube and a 15 cm stem. I'd like to see that bike.
A few years back we had a really good Retul fitter in the shop. She suggested I might raise my saddle a couple millimeters. Or not. This is essentially how I've been sitting on a bike since 1975.
Last edited by oldbobcat; 03-12-23 at 08:34 PM.
#7
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Yeah, good luck finding a 54 cm frame with a 51 cm virtual top tube. And a 42 cm handlebar on a 54 cm frame with a 100 mm stem? This implies a short build with long legs, short arms and unusually broad shoulders. Does this sound like you?
I've got some geriatric compression going on, too. Nearly all of it's in the spine, so I know my saddle height won't change.But I see a shorter stem sometime in my future. If you've been happy with your Retul fit, I suggest you do something similar.
My proportions have been confounding numbers-based fit systems since 1980, starting with the Fit Kit. Wrench Science put me on a 59 cm frame with a 54 cm top tube and a 15 cm stem. I'd like to see that bike.
A few years back we had a really good Retul fitter in the shop. She suggested I might raise my saddle a couple millimeters. Or not. This is essentially how I've been sitting on a bike since 1975.
I've got some geriatric compression going on, too. Nearly all of it's in the spine, so I know my saddle height won't change.But I see a shorter stem sometime in my future. If you've been happy with your Retul fit, I suggest you do something similar.
My proportions have been confounding numbers-based fit systems since 1980, starting with the Fit Kit. Wrench Science put me on a 59 cm frame with a 54 cm top tube and a 15 cm stem. I'd like to see that bike.
A few years back we had a really good Retul fitter in the shop. She suggested I might raise my saddle a couple millimeters. Or not. This is essentially how I've been sitting on a bike since 1975.


hsea17
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After trying the site, I could never recommend it. I'm sure the measurements I took are not 100% accurate, but the numbers it showed are insane!!!! It had the saddle 3 CM (not mm) higher than what I have, which is HOP. (Just for the heck of it, I tried that. At bottom of pedal stroke, my leg was at a 0° bend!!) And their reach was 10 CM (not mm) longer than what I had!!!! (Would need 180 - 200 mm stem for that!!)
#10
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hsea17
#11
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After trying the site, I could never recommend it. I'm sure the measurements I took are not 100% accurate, but the numbers it showed are insane!!!! It had the saddle 3 CM (not mm) higher than what I have, which is HOP. (Just for the heck of it, I tried that. At bottom of pedal stroke, my leg was at a 0° bend!!) And their reach was 10 CM (not mm) longer than what I had!!!! (Would need 180 - 200 mm stem for that!!)
hsea17
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Did some approximations for some numbers, but not crazy ones. Got a very close match to my saddle height and setback. But I also got a Stack of 423mm.
I challenge you to find a bike with a stack that low. The smallest SuperSix has a stack 8cm higher.
I challenge you to find a bike with a stack that low. The smallest SuperSix has a stack 8cm higher.
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Competitive Cyclist used to take measurements and offered 3 fitting alternatives. French fit, the Eddy fit, and Competition fit.
For cyclists with many years of experience and prior fittings, take an outlier calculation with a grain of salt.
Good luck.
For cyclists with many years of experience and prior fittings, take an outlier calculation with a grain of salt.
Good luck.
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FYI, the French fit was the tallest and shortest. The Eddy fit lowered and extended the reach of the handlebar, and the competition fit lowered the bar some more but pulled in the reach to somewhere between French and Eddy. Take them with a grain of salt because handlebar bends, brake hoods, and saddle setbacks have changed over the last 30-40 years.
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@oldbobcat - not the case for me regarding top tube, stem, setback.
French fit: top tube = 59.3 - 59.7; stem = 10.8 - 11.4
Eddy fit: top tube = 58.1 - 58.5; stem = 10.6 - 11.2
Adding the extremes:
French = 70.1 - 71.1cm
Eddy = 68.7 - 69.7cm
The Eddy fit shows 0.5cm setback v 0 for French. Brings the numbers closer.
I have enough bikes over a range of sizes that I have adapted to a different feel. For rides up to about 40 miles all are 'comfortable'. Longer rides or hills/mts will have me focusing on only a few but that is usually a gearing selection (or a saddle preference) over fit concerns.
French fit: top tube = 59.3 - 59.7; stem = 10.8 - 11.4
Eddy fit: top tube = 58.1 - 58.5; stem = 10.6 - 11.2
Adding the extremes:
French = 70.1 - 71.1cm
Eddy = 68.7 - 69.7cm
The Eddy fit shows 0.5cm setback v 0 for French. Brings the numbers closer.
I have enough bikes over a range of sizes that I have adapted to a different feel. For rides up to about 40 miles all are 'comfortable'. Longer rides or hills/mts will have me focusing on only a few but that is usually a gearing selection (or a saddle preference) over fit concerns.
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#16
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For any and all bike geometry, you will need to refer to the manufacturers geometry charts on their website. manufacturers make changes from year to year as well as have different S/R for a given size frame. Example, a 56cm Madone & Emonda S/R = 56.3/39.1 while the Domane S/R = 59.1/37.7. All 3 are 56cm
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For any and all bike geometry, you will need to refer to the manufacturers geometry charts on their website. manufacturers make changes from year to year as well as have different S/R for a given size frame. Example, a 56cm Madone & Emonda S/R = 56.3/39.1 while the Domane S/R = 59.1/37.7. All 3 are 56cm